River Murray Minister Paul Caica said as of Thursday, it was possible to release the water because local inflows from the Finniss River and Currency Creek have rapidly increased water levels in Goolwa Channel to 70cm above sea level.

Regulators were constructed in the Goolwa Channel, near Clayton, and in Currency Creek to increase water levels in the channel and protect the area from acid sulfate soils.

“Water hasn’t flowed over the Goolwa Barrage since 2006 and this has led to a significant reduction in habitat for birds and native fish in the Coorong estuary and increased salinity in the Goolwa Channel,’’ Mr Caica said.

“Water will be released progressively to allow the environment downstream of the barrage to adjust to the changing salinity conditions, initially through one section of the barrage located between the vertical slot fishway and Hindmarsh Island.

“With further rain forecast over the Eastern Mount Lofty Ranges this weekend, the water levels in the Goolwa Channel may increase further.’’

Mr Caica said the freshwater mixing with the seawater on the Coorong side of the barrage will stimulate the ecology of the region by rejuvenating the Coorong mudflats, which are essential for the lifecycle of birds and fish.

“Over the coming weeks, the environmental flow releases through the barrage will also utilise fish passages, meaning native fish species will be able to move freely between the Goolwa Channel and the Coorong to breed,’’ he said.

“Fishers are reminded that a 150-metre fishing exclusion zone exists around the Goolwa Barrage. The environmental release of water through the Barrage is critical for the restoration of the Coorong estuary, and for the survival of threatened fish species.

“Additional sections of the barrages will be operated once the water level in the Goolwa Channel reaches 80cm above sea level. This will ensure that the pool level in the Channel does not exceed 85cm above sea level.

"A further benefit of the releases will be reduced salinity in the Goolwa Channel.

“The Murray-Darling Basin Authority has made the decision to release the water in consultation with the South Australian Government.”